The present invention relates to a lubricator for a catheter guide wire.
It is known, for example in angiographic techniques, to insert a catheter having an inflatable balloon at its distal end into a patient. In order to accurately position the catheter, a guide wire is first inserted into the patient, often at a remote site such as the femoral artery and the end of the guide wire is moved towards the target site. In order to achieve this, a guide wire is used which is sufficiently rigid to enable it to be pushed along the blood vessels of the patient and yet sufficiently flexible in order to make the necessary turns along its path within the body. The guide wire is often formed with a curved tip such that the tip may be used to control the path of the distal end of the guide wire. In order to do this, the wire is rotated by the operator. The wire is sufficiently rigid to transmit torque along the length of the wire so as to cause the orientation of the wire, and in particular the orientation of the curved section at the distal end, to rotate in order that the wire can be guided. Furthermore, such guide wires are typically provided with a hydrophilic coating which makes the wire very slippery when wet. This is useful within the context of the animal or human body in that it makes the wire self lubricating whilst it is within the body.
Once the distal end of the wire is in the target region, a catheter is then slid along the wire in order to carry out whichever medical procedure is involved.
It is vitally important that the friction between the guide wire and the catheter is as low as possible since friction causes the movement of the catheter over the guide wire to result in a force being exerted on the guide wire which in turn may give rise to motion of the guide wire within the patient. This is potentially disruptive to the medical procedure and could also give rise to unnecessary injury to the patient.
According to a first aspect of the present invention there is provided a lubricator for a guide wire, the lubricator comprising a chamber or channel having first and second openings formed therein, the openings being dimensioned such that a guide wire can extend through the chamber or channel and contact with the contents of the chamber, said openings being dimensioned so as to be larger than the guide wire such that the lubricator can be moved substantially freely along the guide wire.
It is thus possible to provide an apparatus through which a catheter guide wire, may pass in order that motion of the lubricator with respect to the catheter guide wire causes the surface of the guide wire to be lubricated. Thus the catheter guide wire may be inserted into the patient as described hereinbefore. The lubricator may then be drawn along the path of the guide wire which remains outside of the patient thereby causing the guide wire to become slippery. Thus when the catheter is moved over the guide wire, frictional contact between the catheter and the guide wire will be much reduced. This has the benefit of making it easier for the operator to move the catheter along the guide wire, and also means that less force will be transmitted from the catheter to the patient via the resilience of the guide wire. Furthermore, since there is a clearance between the lubricator and the guide wire, very little friction exists between the lubricator and the guide wire. This means the lubricator can be moved along the guide wire to lubricate it without giving rise to a significant risk of the guide wire moving within the body of the patient.
The lubricator may be made from plastics or some other low cost material such that the lubricator may be disposed of after a single use. This is advantageous since there is always a risk that blood products might contaminate the guide wire (which is only used once) and thereby contaminate the interior of the lubricator.
Preferably the first and second openings are dimensioned so as to substantially correspond to the dimensions of the exterior of the guide wire with a little bit of extra space so as to allow the guide wire to move relatively freely with respect to the lubricator but to prevent liquid from leaking rapidly therefrom. In order to further reduce leaks, the first and second openings may be formed as channels thereby ensuring that the local direction of the guide wire as it passes through the lubricator is aligned with the axes of the channels.
Advantageously a third opening may be provided in fluid flow communication with the chamber or channel such that the chamber may be filled, flooded or topped up if necessary. The third opening may be provided with a self healing membrane, for example of rubber or a similar material, such that a hypodermic needle may be used to inject saline or other lubricant into the chamber or channel and that the puncture hole is substantially sealed once the hypodermic needle is removed.
Preferably the lubricator is pre-filled with sterile saline or other lubricant at manufacture and the apertures thereof are sealed. Advantageously the openings may be sealed with frangible membranes arranged such that the introduction of the medical device, such as a guide wire into the lubricator causes the frangible membranes to be ruptured. It is thus possible to provide a device which is permanently ready for use and sterile.
Preferably one end of the device, namely that end intended to be closest to the patient, is provided with engagement means for engaging a stabilising device. The engagement means may be in the form of resiliently deformable tines, a snap fixing, a screw thread or some other suitable mechanical arrangement. A complimentary fixing is provided on the stabilising device.
The stabilising device is arranged, in use, to encircle the medical device, for example a guide wire, and is provided with engagement members which can be moved between a first position such that they firmly engage the guide wire to a second position such that the guide wire is no longer held by the engagement members and the catheter can be passed through the stabilising device and into the patient. This enables the operator to hold the stabilising device steady, and hence hold the guide wire steady, whilst the guide wire is being lubricated and the catheter is being passed along the guide wire and towards the patient.
The channel is preferably elongate. In one embodiment the channel may be xe2x80x9cclosedxe2x80x9d, that is in a form of a pipe with a continuous outer surface. Thus the channel may, for example, be a cylinder open at opposing ends to form the first and second openings.
Alternatively, the channel may be xe2x80x9copenxe2x80x9d such that the guide wire, or some other medical device can enter the channel from the side. This effectively allows the lubricator to be clipped on or around the guide wire. The channel may be profiled so as to inhibit the accidental lateral removal of the device from the channel. The channel may include a non-linear, for example curved or serpentine, side entry channel and/or may be provided with lips and/or seals, thereby serving to prevent accidental disengagement of the lubricator from the medical device.
As a further alternative the body of the lubricator may be split into opposing parts such that the lubricator can be assembled around the guide wire. The opposing parts may be hingedly connected to one another and/or may engage each other in a snap fit manner or may use some other locking arrangement to hold the body parts together.
Advantageously the at least one supply channel engages with a receptor for a syringe such that the syringe can act as a reservoir for a lubricant. Alternatively a sponge or similar lubricant bearing insert may be provided within the body so as to act as a reservoir. The sponge like insert may be removable and replaceable. If a sufficiently rigid sponge is used the sponge may form the body of the lubricator. In such circumstances it is desirable that the outer surface of the sponge be treated to make it impermeable.